The preparation of illustrations for reports of the United States Geological survey : with brief descriptions of processes of reproduction
A 1920 Government Printing Office manual by John L. Ridgway for the United States Geological Survey, explaining how to prepare drawings for reproduction in federal scientific reports. The pictures are technical diagrams: geological cross-sections with contour-like curved lines, a dense tangle of intersecting survey lines, a plat sheet with township and range labels, and a projection grid with latitude and meridian markings. A designer might take their precise linework, hatching, and grid structure as models for abstract technical patterns.
